The present invention relates to a deflection yoke for mounting on a color cathode ray tube and more particularly to a deflection yoke provided with a convergence correction means.
In a conventional device, E-shaped and U-shaped magnetic substances were disposed on an electron gun side of a deflection yoke and vertical auxiliary coils applied with a vertical deflecting current were wound on the above-described respective magnetic substances so as to correct various misconvergences as described in JP-A-63-143727.
In an apparatus according to another prior art, a dynamic convergence correction means consisting of coils which were wound around eight pieces of magnetic cores arranged being apart from each other on concentric circles with respect to a tube axis was held on a self-convergence deflection yoke as described in JP-A-57-180286.
In abovesaid prior art, the configuration of the magnetic substance on which a vertical auxiliary coil is wound is not a ring shape. Accordingly, the operation of shielding a horizontal deflecting magnetic field was weak, and, when a horizontal deflection coil and a vertical coil were formed in a saddle form having little leakage magnetic field, improvement of convergence performance has been inconsistent with reduction of barrel-shaped image distortion (hereafter referred to as barrel distortion).
In addition, correction of cross misconvergence produced between a raster produced by a center beam and a raster produced by a side beam and correction of rotation of a transverse raster or a longitudinal raster have not been made with above-described prior art.